Season 4 - Episode 7: Invisible Evidence

Episode 7: Invisible Evidence

Warrick testifies in a rape/murder trial, but the defense gets the key piece of evidence, a bloody knife, thrown out on a technicality. CSI is given a 24-hour continuance to process the remaining 'unprocessed' evidence or discover a new link tying the suspect. With further investigation, the CSIs begin to question if the suspect is actually guilty.